1. Field of the Invention
The present invention relates to an improved radio controlled yacht and more particularly to improvement of or relating to a radio controlled yacht adapted to allow control of the movement of its sail and rudder with the aid of a radio control unit which is called a propo, as well as to a structure of the sail for the radio controlled yacht.
2. Description of the Prior Art
A so-called radio controlled yacht sails on water under the influence of natural wind force while the extent of movement of its sail and the angle of movement of its rudder are controlled with the aid of a radio control unit (hereinafter referred to as a propo) which essentially comprises a sender, a receiver and servos. As propos have been widely used in recent years, a variety of radio controlled models such as radio controlled boats, radio controlled aeroplanes and the like have been developed. As far as a radio controlled yacht is concerned, things are different from other radio controlled models and conventional servo cannot be employed therefor. Specifically, since a radio controlled yacht sails on water under the influence of natural wind force, the extent of movement of its sail should be adjusted properly in order to assure optimum sailing conditions. Adjustment of the extent of movement of a sail has been hitherto carried out by causing sheets attached to a boom of the sail to be extended or contracted with the aid of a servo. In view of the fact that the sail on a real yacht is ready to swing from the close hauled position where it has a limited extent of free movement to the running position where it has a relatively high freedom of movement, it is required that a radio controlled yacht has a sufficiently high extent of movement of its sail to assure that it sails on water in a manner similar to a real yacht. However, all conventional servos fail to have a sufficiently long sheet stroke and for that reason a sail servo specially designed for a radio controlled yacht has been developed which has a structure different from the conventional one.
To facilitate understanding of the invention it will be helpful that a radio controlled yacht with the conventional sail servo mounted thereon be described below by reference to FIG. 1. A radio controlled yacht 1 is constructed in the sloop style which includes a main sail 2 and a jib sail 3. The main sail 2 has a main boom 4 secured to the lower edge thereof and a main sheet 5 is attached to the one end of the main boom 4. On the other hand, the jib sail 3 has a jib boom 6 disposed therebelow and a jib sheet 9 is attached to the one end of the jib boom 6. The jib boom 6 is rotatable about a pin 8 which stands upright on the deck 7. As mentioned above, to the one end of the jib boom is attached the jib sheet 9 which extends rearward to a guide bolt 11 by way of a plurality of heatons 10. Further, after passing through the guide bolt 11, the jib sheet 9 is wound about a winding reel 13a of a sail servo 13 together with the main sheet 5 which has been passed through the guide bolt 12. The sail servo 13 is constructed by a combination of electronic circuits, a motor, a speed reduction gearing, pulleys and other components, said motor generating higher power than the conventional one and said speed reduction gearing being designed in a high speed reduction ratio. The sail servo 13 is operatively connected to another servo 14 therefor which is disposed in parallel to a rudder servo 15 in a spaced relation. The rudder servo 15 is operatively connected to a rudder shaft 17 via a linkage 16. The second servo 14 and the rudder servo 15 are substantially identical to one another in structure. In the drawing, reference numeral 18 designates a receiver for the propo and a power supply source 19 for the receiver 18 and another power supply source 20 for the sail servo 13 are disposed in parallel in a spaced relation at a position located away from the receiver 18. Due to the fact that the sail servo 13 consumes a large amount of electric power there is a necessity for preparing the power supply source 20 for the sail servo 13 independently of the power supply source 19 for the receiver 18.
As will be apparent from the above description, the conventional radio controlled yacht 1 is required to have three servos 13, 14 and 15, two power supply sources 19 and 20 and a single receiver 18 mounted thereon. Among these components the sail servo 13 is designed in larger dimensions with the heaviest weight and the power supply source 20 for the sail servo 13 is considerably heavy. To assure a sufficient amount of buoyancy for carrying these heavy articles the radio controlled yacht 1 is unavoidably designed with a total length of more or less 1 m and moreover it has a considerably wide breadth for the purpose of housing them within the hull. In addition to this there is a necessity to provide a large ballast attached to the bottom of the keel so as to assure that the yacht sails on water safely with the heavy articles mounted thereon. For this reason it is very difficult to fabricate a radio controlled yacht in dimensions accurately reduced in proportion to those of a real yacht in accordance with the conventional concept and therefore there has been a failure to achieve the beautiful appearance inherent to a yacht. Incidentally, a large and powerful sail winch servo has already been provided as a servo for a propo instead of the above-described combination of the sail servo 13 and the second servo 14 for the latter but this sail winch servo is also designed in larger dimensions, and is heavy in weight, and therefore it has not been possible for a radio controlled yacht to be fabricated in smaller dimensions.
As the same time, a sail to be mounted on the conventional radio controlled yacht is unavoidably designed in larger dimensions corresponding to the dimensions of the hull of the yacht. Since the conventional sail is usually produced by sewing fabric material, it has a considerable weight. As such a sail is produced in larger dimensions, the wind pressure exerted thereon increases correspondingly and its weight increases too. For this reason it is impossible to carry out proper control operations for the sail unless a specially designed sail servo is mounted on the hull. Thus, to allow a radio controlled yacht to be designed and fabricated in smaller dimensions with a lighter weight, it is essentially necessary to develop a yacht sail having small dimensions and light weight which can be controlled with the aid of a servo motor constructed in the same manner as the conventional rudder servo.
Hence, the present invention has been made with the foregoing problems in mind and its object resides in providing a radio controlled yacht and a sail for the same which are entirely free from these drawbacks.
Specifically, it is an object of the present invention to provide an improved radio controlled yacht which is designed and fabricated in dimensions reduced exactly in proportion to those of a real yacht and which has smaller dimensions and a lighter weight than those of the conventional one.
It is another object of the present invention to provide an improved sail for the radio controlled yacht as described above which is designed and easily fabricated in smaller dimensions with a lighter weight than the conventional sail while having an appearance very similar to that of a real yacht and which can generate a higher propulsive force under the influence of natural wind force when it is filled with wind.
Other objects, features and advantages of the present invention will become more clearly apparent from a reading of the following which has been prepared in connection with the accompanying drawings.